Coupling assembly for wheel and axle

ABSTRACT

A wheel, by which a base is configured to be wheeled across a floor, includes a tread and a hub. The hub has an inner surface that surrounds an axis and defines a bore. The hub further has an outer surface surrounding the inner surface and a slot extending radially outward from the bore to the outer surface. A shaft is centered on the axis and coupled to the base. The shaft is configured to be received in the bore and has a groove. A clip is configured to be attached to the hub in an installed position in which the clip extends from within the groove outward through the slot to secure the hub to the shaft. The installed position is axially between the base and the tread.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a division of U.S. application Ser. No. 11/194,981, filed Aug.2, 2005 now U.S. Pat. No. 7,278,693, which is hereby incorporated byreference.

TECHNICAL FIELD

This technology relates to coupling assemblies, such as those forattaching a wheel to an axle.

BACKGROUND

A vacuum cleaner includes a base housing and front and rear wheels forwheeling the cleaner about a floor. The rear wheels are attached by acoupling assembly to a common rear axle that is rotatably connected tothe housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vacuum cleaner including two rearwheel assemblies attached to an axle.

FIG. 2 is an expanded perspective view of one of the wheel assemblies.

FIG. 3 is an exploded view of parts shown in FIG. 2.

FIG. 4 is a sectional view of the axle, taken at line 4-4 of FIG. 3.

FIG. 5 is a sectional view of a hub of the wheel assembly, taken at line5-5 of FIG. 3.

FIG. 6 is a sectional view of a clip of the wheel assembly.

FIGS. 7-8 are sectional views illustrating a first method of attachingthe wheel assembly to the axle.

FIGS. 9-10 are sectional views of the assembly attached to the axle.

FIGS. 11-12 are sectional views illustrating a first method of detachingthe wheel assembly from the axle.

FIGS. 13-14 are sectional views illustrating a second method ofdetaching the wheel assembly from the axle.

FIGS. 15-16 are sectional views illustrating a second method ofdetaching the wheel assembly from the axle.

FIGS. 17-18 are sectional views illustrating a third method of detachingthe wheel assembly from the axle.

FIG. 19 is a sectional view illustrating a fourth method of detachingthe wheel assembly from the axle.

DESCRIPTION

Apparatus

The apparatus 1 shown in FIG. 1 has parts that are examples of theelements recited in the claims. The apparatus 1 thus includes examplesof how a person of ordinary skill in the art can make and use theclaimed invention. It is described here to meet the requirements ofenablement and best mode without imposing limitations that are notrecited in the claims.

The apparatus 1 is a vacuum cleaner for cleaning a floor 6. It includesa base 10, a handle 14 extending upward from the base 10 and a filterbag 20 suspended from the handle 14. The base 10 includes a base housing24 with a nozzle 26. Front and rear wheels 30 and 32 are rotatablyconnected to the housing 24 to enable wheeling the base 10 over thefloor 6. A fan 36 in the housing 24 generates a flow of air that carriesdirt from the floor 6, through the nozzle 26, the fan 36 and a fill tube38 into the bag 20.

Each rear wheel 32 is removably attached by a coupling assembly 40 to acorresponding end of a shaft 50, in this case an axle. The axle 50 isrotatably connected to the housing 24 by bearings 54. The wheel 32 andthe coupling assembly 40 together comprise a wheel assembly 60, onelocated at each end of the axle 50. The wheel assemblies 60 areidentical. They are described as follows with reference to one of thewheel assemblies 60.

As shown in FIG. 2, each coupling assembly 40 comprises a hub 42 and aclip 44 configured to attach the wheel 32 to the axle 50. The clip 44 isshown in an installed position, securing the hub 42 to the axle 50.

The axle 50 is shown in FIGS. 3-4. It is centered on an axis 61. It hasan outer surface 70 with multiple sections. These include a frontsection 72, a cylindrical section 74 spaced rearwardly from the frontsection 72, a frustoconical beveled section 76 flaring outward from thefront section 72 to the cylindrical section 74, and a flat section 78interrupting the cylindrical section 64. A groove 80 extendscircumferentially about the cylindrical surface 74 and across the flatsection 78. The groove 80 is defined by two axially opposing sidesurfaces 82 and a radially inner surface 84. The radially inner surface84 is round, with a radius R1 that is smaller than a radius 12 of thecylindrical section 74. The front, cylindrical and beveled surfacesections 72, 74 and 76 and the groove 80 are centered on the axis 61.

The wheel 32 is shown in FIG. 3. It is centered on its axis of rotation91, which coincides with the axis 61 of the axle 50 when the wheel 32 isattached to the axle 50. The wheel 32 has a flat axially outer surface92, a ribbed axially inner surface 94, and a radially outer treadsurface 96 centered on the axis 91.

The hub 42 is shown in FIGS. 3 and 5. It is permanently fixed to, andextends axially inward from, the wheel 32. The hub 42 has a radiallyouter surface 100 surrounding a radially inner surface 102 that definesan axially extending bore 103. The inner surface 102 is configured toclosely receive the axle 50. The inner surface 102 includes acylindrical section 104 and a flat section 108 that are configured torespectively mate with the cylindrical and flat surface sections 74 and78 of the axle 50. Accordingly, the cylindrical inner surface section104 of the hub 42 has a radius R3 that equals or slightly exceeds theradius R2 (FIG. 4) of the cylindrical outer surface section 74 of theaxle 50.

Upper and lower arcuate slots 111 and 112 extend in radially oppositedirections perpendicular to the axis 91, from the bore 103 to theradially outer surface 100. The slots 111 and 112 are identical andlocated symmetrically opposite each other about the axis 91. Each slot111 and 112 extends 180° circumferentially about the axis 91 and isdefined by a pair of axially opposing parallel side surfaces 114 and apair of circumferentially opposing coplanar end surfaces 116. The clip44 is shown in FIG. 6. It is a spring clip formed of bent length ofelastic metal wire with a cylindrical cross-sectional profile. The pathfollowed by the wire is planar in that it is located on a single plane117 along its entire length. The path is also symmetric about a line ofsymmetry 118 located on the plane 117. The shape of the clip 44 can bedescribed as follows with reference to an imaginary reference point 119about which the clip 44 extends. The reference point 119 is on the lineof symmetry 118 and falls on the axes 61 and 91 (FIG. 3) when thecoupling assembly 40 is attached to the axle 50.

The clip 44 has five sections 121, 122, 123, 124 and 125 disposedsequentially along the length of the clip 44. The first and fifthsections 121 and 125 are straight. The second, third and fourth sections122, 123 and 124 are circular. The five sections are coplanar in thatthey lie on a common plane.

The first and second sections 121 and 122 meet at a first bend 131 inthe clip 44, bounded by dashed boundary lines B1 and B2. The bend 131 isa radially outward bend with respect to the reference point 119.Similarly, the second and third sections 122 and 123 meet at a secondradially outward bend 132 in the clip 44, bounded by dashed boundarylines B3 and B4. Likewise, the third and fourth sections 123 and 124 andthe fourth and fifth sections 124 and 125 respectively meet at third andfourth radially outward bends 133 and 134 in the clip 44. Each bend 131,132, 133 and 134 defines an angle α1 of more than 60°, less than 120°,about 60° to about 120°, and preferably of about 90°

Each bend 131, 132, 133 and 134 is bounded by a respective convex edge141, 142, 143 and 144, lying on the plane 117 and facing the referencepoint 119, that is preferably round. The radius of each convex edge 141,142, 143 and 144 is smaller than the radially extending depth of theslot 111 and 112, and can even be zero to define a sharp right angle.

The second and fourth sections 122 and 124 are circumferential grippingsections in that they are configured to extend circumferentially withinthe axle groove 80 (FIG. 3) to grip and secure the axle 50. The grippingsections 122 and 124 are circularly bowed, diametrically opposed,symmetric about the reference point 119, and mirror images of each otherwith respect to the line of symmetry 118. Each gripping section 122 and124 has, lying on the plane 117, a concave radially inner edge 151 and aconvex radially outer edge 152. Each inner and outer edge 151 and 152defines an arc A1 of more than 60°, less than 120°, about 60° to about120°, and preferably of about 90°.

The third section 123 is a radial bridging section in that it extendsradially outward from an end of each gripping section 122 and 124 tobridge from one gripping section 122 to the other 124. It is C-shapedand thus defines an arc A2 of more than 180°, centered on a referencepoint 159 on the line of symmetry 118. In this example, the arc A2 ismore than 240°, and preferably more than 270°. Relative to other shapes,such as oval, the circular shape improves the spring bias retaining thegripping sections 122 and 124 in the axle groove 80. The bridgingsection 123 defines an inner edge 160 that lies on the plane 117 andextends from the second convex edge 142 to the third convex edge 143.

The radius of the inner edge 160 is greater than the radii of the inneredges 151 of the gripping sections 122 and 124. The diameter of theinner edge 160 is greater than the distance between the inner edges 151of the gripping sections 122 and 124 as measured through the referencepoint 119, or through the axes 61 and 91 (FIG. 3) when the clip 44 isinstalled.

The first and fifth sections 121 and 125 are radial end sections in thatthey extend radially outward from ends of the gripping sections 122 and124 to distal ends 178 of the clip 44. The end sections 121 and 125 havestraight edges 161 and 165 that lie on the plane 117 and respectivelyextend radially outward from the first and fourth convex edges 141 and144 to the distal ends 178.

In its installed position, the bridging and end sections 123, 121 and125 extend radially outward through the slots 111 and 112 (FIG. 2) alongfour imaginary lines 181, 182, 183 and 184. The imaginary lines 181,182, 183 and 184 meet in the axle 50 (FIG. 2) and preferably at or atleast near the axis 61. They are sequentially spaced about the axis 61by, and meet at, angles α2, α3 and α4 of more than 60°, less than 120°,about 60° to about 120°, and preferably of about 90°. The angles α3 andα4 are preferably approximately equal.

Procedure for Attaching the Hub to the Axle

A method for attaching the coupling assembly 40 to the axle 50 isillustrated in FIG. 3. First, the clip 44 is positioned beside the hub42 such that its end sections 121 and 125 are directed toward respectiveslots 111 and 112. The clip 44 is moved toward the hub 42 as indicatedby arrow 207. As the clip 44 is moved, the bends 131, 132, 133 and 134of the clip 44 slide up the outer surface 100 of the hub 42 and over theend surfaces 116 until the gripping sections 122 and 124 drop into theslots 111 and 112. This brings the clip 44 into its installed positionon the hub 42 as shown in FIG. 7.

In the installed position of the clip 44 shown in FIG. 7, spring bias ofthe bridging section 123 of the clip 44 retains the arcuate inner edges151 of the gripping sections 122 and 124 of the clip 44 in the bore 103.Transverse movement of the clip 44 relative to hub 42 is prevented byabutment of the bends 131, 132, 133 and 134 of the clip 44 against theend surfaces 116 of the slots 111 and 112.

As shown in FIG. 8, axial movement of the clip 44 relative to the hub 42is prevented by abutment of the sections 121, 122, 123, 124 and 125 ofthe clip 44 against the side surfaces 114 of the slots 111 and 112.

Next, the axle 50 is positioned in front of the hub 42, with its axis 61coinciding with the axis 91 of the hub 42. The axle 50 is inserted intothe bore 103 of the hub 42 as indicated by arrow 217. As the axle 50 isinserted, the arcuate inner edges 151 of the gripping sections 122 and124 of the clip 44 slide up and over the beveled and cylindrical surfacesections 76 and 74 of the axle 50 and drop into the groove 80. Thisbrings the hub 42, and thus the wheel 32, into a removably installedposition on the axle 50 as shown in FIGS. 9 and 10.

With the hub 42 thus attached to the axle 50, the following features areapparent: Spring bias of the bridging section 123 of the clip 44 retainsthe arcuate inner edges 151 of the gripping sections 122 and 124 in theaxle groove 80. The arcuate inner edges 151 extend circumferentiallythrough the groove 80, while the arcuate outer edges 152 of the grippingsections 122 and 124 extend circumferentially through the hub slots 111and 112. At least a portion of each convex edge 141, 142, 143 and 144 isin the groove 80.

Contiguous edges 161, 141, 151, 142 and 160 described above togetherdefine a continuous edge that extends from one of the distal ends 178,radially inward through the first slot 111 into the groove 80,circumferentially through the groove 80, and radially outward from thegroove 80 through and beyond the slot 111.

Axial movement of the axle 50 relative to the clip 44 is prevented byabutment of the gripping sections 122 and 124 of the clip 44 against theside surfaces 82 of the groove 80. Rotary movement of the axle 50relative to the hub 42 is prevented by abutment of the flat section 78of the axle 50 with the flat section 108 of the hub 42. The clip 44 thusengages and establishes a mechanical interlock between the hub 42 andthe shaft 50.

The end sections 121 and 125 and the bridging section 123 extendradially outward from the gripping sections 122 and 124 through andbeyond the slots 111 and 112 of the hub 42. The ends 178 of the clip 44are located outside the hub 42.

The bridging section 123 extends arcuately about the hub 42 from thefirst slot 111 to the second slot 112. A central side location 213 onthe outer surface 100 of the hub 42 is located circumferentially midwaybetween the slots 111 and 112. The central side location 213 is spacedfrom and faces the bridging section 123. Accordingly, a space 215 existsbetween the hub 42 and the bridging section 123 at the central sidelocation 213. A portion of the bridging section 123 that is outside theslots 111 and 112 and spaced from the hub 42 defines a circular arc A3of more than 180°, preferably more than 210°, and more preferably morethan 240°.

The groove 80 can be continuous or discontinuously segmented. In theexample shown in FIG. 9, the groove 80 is continuous, because itcomprises upper and lower portions 221 and 222 connected to each otherby two opposite side portions 223 and 224. However, only the upper andlower portions 221 and 222 receive the clip 44. Since the side portions223 and 224 are not needed, they can be omitted. In that case, thegroove 80 would be discontinuous, because the upper and lower portions221 and 222 would not be connected to each other by the side portions223 and 224. But the upper and lower portions 221 and 222 would still beparts of “the groove 80”.

Another method for attaching the coupling assembly 40 to the axle 50 isillustrated in FIGS. 11 and 12. First, as shown in FIG. 11, the axle 50is inserted into the hub 42 until its front section 72 abuts an axiallyinner wall 234 of the hub 42. The axle 50 is configured for this tobring the axle groove 80 into axial alignment with the slots 111 and112. Next, as indicated by arrow 237 in FIG. 12, the clip 44 is movedtoward and into its installed position, shown in FIG. 13.

Procedure for Detaching the Hub from the Axle

There are several possible methods for detaching the hub 42, and thusthe wheel 32, from the axle 50. One method is illustrated in FIG. 13.The bridging section 123 is pushed toward the hub 42 with a screwdriver251 in a transverse direction, indicated by arrow 257. The bridgingsection 123 is moved into abutment with the outer surface 100 of the hub42 as shown in FIG. 14. This moves the first and fourth bends 131 and134 out of the hub 42, moves the second and third bends 132 and 133 ontoa pair of the end surfaces 116, and pulls the gripping sections 122 and124 out of the axle groove 80. The axle 50 can then be withdrawn fromthe hub 42. As shown in FIG. 13, this procedure is enabled by the space215 between the bridging section 123 and the hub 42 providing sufficientroom for the bridging section 123 to move sufficiently far toward thehub 42 to bring the gripping sections 122 and 124 out of the axle groove80.

A second possible method for detaching the wheel 32 is illustrated inFIG. 15. A hook 261 is inserted in the space 215 between the bridgingsection 123 and the hub 42. The hook 261 pulls the bridging section 123away from the hub 42 in a transverse direction indicated by arrow 267.This, as shown in FIG. 16, moves the second and third bends 132 and 133of the clip 44 out of the hub 42, moves the first and fourth bends 131and 134 onto a pair of the end surfaces 116, and pulls the grippingsections 122 and 124 out of the axle groove 80. The axle 50 can then bewithdrawn from the hub 42. If desired, the hook 261 can pull the clip 44completely off the hub 42.

The first and second methods described above thus enable the grippingsections 122 and 124 of the clip 44 to be pulled out of the groove 80 bymoving the clip 44 in either of two radially opposite transversedirections 257 and 267 (in FIGS. 13 and 15, respectively).

A third method of detaching the wheel 32 is illustrated in FIG. 17. Atool 271 engages the end sections 121 and 125 of the clip 44 where theyprotrude from the hub 42 and pries them apart against bias of thebridging section 123. This spreads the bridging section 123 open,pulling the gripping sections 122 and 124 out of the axle groove 80, asshown in FIG. 18. The axle 50 can then be withdrawn from the hub 42.When the tool 271 releases the clip 44, the clip 44 will automaticallysnap back into its installed position. This is in contrast to the firstand second methods described above, which require the clip 44 to bemanually pushed transversely back into its installed position.

A fourth method of detaching the wheel 32 is illustrated in FIG. 19. Thetool 271 is inserted into the space 215 bordered by the hub 42 and thebridging section 123. The tool 271 engages opposite locations of thebridging section 123 to spread it open. This pulls the gripping sections122 and 124 out of the axle groove 80, enabling the axle 50 to bewithdrawn from the hub 42.

The coupling assembly 40 (FIG. 2), comprising the hub 42 and clip 44, iswell suited for coupling a wheel 32 to an axle 50, as described above.However, the coupling assembly 40 can also be used to couple otherdevices together, such as to couple a crank to a shaft that is not anaxle.

SUMMARY

Accordingly, the apparatus 1 provides an example of the followingfeatures: A wheel 32, by which a base 10 is configured to be wheeledacross a floor 6, includes a tread 96 and a hub 42. The hub 42 has aninner surface 102 that surrounds an axis 91 and defines a bore 103. Thehub 42 further has an outer surface 100 surrounding the inner surface102 and a slot 111 extending radially outward from the bore 103 to theouter surface 100. A shaft 50 is centered on the axis 91 and coupled tothe base 10. The shaft 50 is configured to be received in the bore 103and has a groove 80. A clip 44 is configured to be attached to the hub42 in an installed position in which the clip 44 extends from within thegroove 80 outward through the slot 111 to secure the hub 42 to the shaft50. The installed position is between the base 10 and the tread 96.

The apparatus 1 further provides an example of the following features:The clip 44 can be pulled by a hook 261 in a radially outward directionto withdraw the clip 44 from the groove 80 to release the hub 42 fromthe shaft 50. The clip 44 can also be pushed in a direction opposite theradially outward direction, to withdraw the clip 44 from the groove 80to release the hub 42 from the shaft 50. In the installed position ofthe clip 44, a space 215 exists, between the hub 42 and the clip 44,into which a hook 261 can be inserted to pull the clip 44 transverselyoff of the hub 42. The slot 111 is one of first and second slots 111,112 extending in radially opposite directions 215, 267 from the bore 103to the outer surface 100, and in the clip's installed position, firstand second sections 121, 125 of the clip 44 extend from within thegroove 80 outward through the first and second slots 111, 112 to securethe hub 42 to the shaft 50. The shaft's outer surface 70 has acylindrical section 74 and a flat section 78, and the hub's innersurface 102 has a cylindrical section 104 and a flat section 108configured to respectively mate with the cylindrical and flat sections74, 78 of the shaft 50. The hub 42 includes an end surface 116 borderingthe slot 111, onto which a portion of the clip 44 can slide to pull theclip 44 out of the groove 80 as the clip 44 is moved in a lineartransverse direction. The hub 42 has an axially inner wall 234 thatabuts the shaft 50 when the groove 80 is axially aligned with the slot111. The base 10 is a vacuum cleaner base. In its installed position,the clip 44 is accessible only through a clearance between the base 10and the tread 96.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have elements that do not differ fromthe literal language of the claims, or if they include equivalentstructural elements with insubstantial differences from the literallanguage of the claims.

1. An apparatus comprising: a base; a wheel by which the base isconfigured to be wheeled across a floor, the wheel including a tread anda hub, the hub having an inner surface surrounding an axis and defininga bore, an outer surface surrounding the inner surface, and a slotextending radially outward from the bore to the outer surface; a shaftthat is centered on the axis and coupled to the base and configured tobe received in the bore and has a groove; and a clip configured to beattached to the hub in an installed position in which the clip extendsfrom within the groove outward through the slot to secure the hub to theshaft, the installed position being axially between the base and thetread; wherein the clip is configured to be pulled by a hook in aradially outward direction to withdraw the clip from the groove torelease the hub from the shaft; and the clip can also be pushed in adirection opposite said radially outward direction, to withdraw the clipfrom the groove to release the hub from the shaft.
 2. The apparatus ofclaim 1 wherein, in the installed position of the clip, a space exists,between the hub and the clip, into which a hook can be inserted to pullthe clip transversely off of the hub.
 3. The apparatus of claim 1wherein the slot is one of first and second slots extending in radiallyopposite directions from the bore to the outer surface, and in theclip's installed position, first and second sections of the clip extendfrom within the groove outward through the first and second slots tosecure the hub to the shaft.
 4. The apparatus of claim 1 wherein theshaft has an outer surface with a cylindrical section and a hat section,and the hub has an inner surface with a cylindrical section and a flatsection configured to respectively mate with the cylindrical and flatsections of the shaft.
 5. The apparatus of claim 1 wherein the hubincludes an end surface bordering the slot, onto which a portion of theclip can slide to pull the clip out of the groove as the clip is movedin a linear transverse direction.
 6. The apparatus of claim 1 whereinthe hub has an axially inner wall that abuts the shaft when the grooveis axially aligned with the slot.
 7. The apparatus of claim 1 wherein,in its installed position, the clip is accessible through clearancebetween the base and the tread.
 8. The apparatus of claim 1 wherein thebase is a vacuum cleaner base.
 9. An apparatus comprising: a base; awheel by which the base is configured to be wheeled across a floor, thewheel including a tread and a hub, the hub having an inner surfacesurrounding an axis and defining a bore, an outer surface surroundingthe inner surface, and a slot extending radially outward from the boreto the outer surface; a shaft that is centered on the axis and coupledto the base and configured to be received in the bore and has a groove;and a clip configured to be attached to the hub in an installed positionin which the clip extends from within the groove outward through theslot to secure the hub to the shaft, and in which the clip is accessiblethrough a clearance between the base and the tread to withdraw the clipfrom the groove to release the hub from the shaft; wherein the clip isconfigured to be pulled by a hook in a radially outward direction towithdraw the clip from the groove to release the hub from the shaft; andthe clip can also be pushed in a direction opposite said radiallyoutward direction, to withdraw the clip from the groove to release thehub from the shaft.
 10. The apparatus of claim 9 wherein the shaft hasan outer surface with a cylindrical section and a flat section, and thehub has an inner surface with a cylindrical section and a flat sectionconfigured to respectively mate with the cylindrical and fiat sectionsof the shaft.
 11. The apparatus of claim 9 wherein the base is a vacuumcleaner base.